1. Field of the invention
The invention relates to blends of high modulus thermoplastic polymer material based on commercial polyethyleneterephthalate (PET) and polybutyleneterephthalate (PBT) useful for preparing various shaped objects such as film, sheets, and the like.
2. Prior Art
It is known that orientation of polymers improves substantially their mechanical properties (Ultra-High Modulus Polymers, Leningrad, Chimija (1983) (in Russian); identical to Ciferri and Ward, Ultra-High Modulus Polymers Applied Science Publishers (1977), 227-231. Two-stage drawing of PET, the first stage at room temperature and the second one after annealing at a temperature close to the melting point, results in a high degree of orientation (15-20:1) and leads to an improvement of the mechanical strength of the polymer (K. Slusallek, H. C. Zachmann, Kolloid Z. Z. Polymere, 251 (1973) 865; Angew. Makromol. Chem., 53 (1976) 35). Increase in the degree of orientation can also be achieved by increasing the molecular weight of polycondensation polymers through additional solid state polycondensation (Slusallek et al., loc. cit.; S. Fakirov et al., IUPAC Intern. Symp. on Macromol., Aberdeen (1974), Abstr. Book p. 85). The disadvantages of the known materials are due to the fact that their moduli are not sufficiently high and their achievement requires high energy consumption.